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大家知道,渗碳过程中最难控制的参数之一是表面含碳量。当表面含碳量过高时,就会形成大量的碳化物、残留奥氏体及贝氏体等有害机械性能的组织,形成太厚的过共析层,使齿根疲劳强度和冲击韧性大为下降,并且齿角容易崩裂,磨削时极易产生磨削裂纹。所以渗碳时不希望出现过共析层。但是,当表面含碳量过低时,淬火后齿表面易形成非马氏体产物,从而降低了齿表面硬度和有效渗层的深度,使耐磨性大大降低,直接影响使用寿
We all know that one of the most difficult parameters to control during carburization is the carbon content of the surface. When the surface carbon content is too high, it will form a large number of carbide, retained austenite and bainite and other harmful mechanical properties of the organization, the formation of too thick eutectic layer, the root fatigue strength and impact toughness For the decline, and the tooth angle is easy to crack, grinding is easy to produce grinding cracks. So do not want carburizing eutectoid layer. However, when the carbon content of the surface is too low, the surface of the tooth is easily formed with non-martensite after quenching, thereby reducing the hardness of the tooth surface and the depth of the effective permeation layer, greatly reducing the abrasion resistance and directly affecting the service life